Fault tolerant packet switched network design using capacity augmentation

A design method for packet-switched networks is presented that enhances the reliability and prevents the performance degradation caused by network failures. The method is based on a design technique wherein the redundant capacity is assigned to appropriate links in advance to be capable of accommodating the detoured traffic caused by failed links. Using this technique, it is crucial to accurately evaluate to how large an amount the capacity for each link must be augmented. An augmented capacity function is introduced, which determines the capacity of a link based on the probability of a particular network state and a parameter which represents how important the link is in the state. Numerical examples are given to demonstrate the feasibility of the method, in terms of cost/performance effectiveness. The relation between the reliability level and the network cost is discussed.<>